Unified braking system - does yours work?

SpeedStar

XT12 and DL650
Founding Member
2011 Site Supporter
2012 Site Supporter
2013 Site Supporter
Vendor
Joined
Sep 17, 2010
Messages
1,388
Location
San Diego, Ca
This is from the Yamaha website:

The ABS and Unified Brake System work together to help prevent wheel lock during braking. This new system allows the rider to operate front and rear brakes together by simply pulling the front brake lever, especially helpful when riding while standing on the pegs. Applying the rear brake first overrides the Unified Braking System to provide traditional separate front and rear brake control.

I thought I would try this yesterday while I was in the garage. I had the bike on the centerstand and turned the rear wheel by hand and then applied the front brake thinking it would stop the rear wheel, and it did not.
Next I thought maybe the bike has to be on, so I tried that, still no rear brake action from the front brake lever.
Then I thought maybe it needs to be moving, so I went out to the street and put it in gear while on the centerstand and got it up to about 10mph and tried it with no braking to rear.

I was just wondering if anyone else has tried this with the same results? Maybe it only works at higher speeds? I just wonder if it is functional.
 

HoebSTer

New Member
Founding Member
2011 Site Supporter
2012 Site Supporter
Joined
Sep 29, 2010
Messages
2,883
Location
ISSAQUAH, WA USA
Devin Speedstar, the only thing I can add at this time is from past experiences with the Honda ST13. When the front is applied, it is only applying 1/3 of the rear caliper, not the whole thing. I would think it would at least stop it while on center stand, but who knows. We may have to get the manual out now.
 

Mellow

Active Member
Founding Member
Joined
Feb 5, 2011
Messages
1,054
Location
Dallas, TX
Being used to the ST1300... didn't matter which you applied first, foot or hand.

On the Tenere, if I hit the foot brake in a panic stop I can chirp the tires as the ABS kicks in. Using the hand brake, that doesn't happen.

That won't happen on the ST1300 and I'm not sure if it's just the extra weight of that bike or Honda just does a better job with ABS. Nothing against the Tenere, it brakes very well, but at the moment the ST1300 feels like it brakes better... just a comparison and not even a scientific one, the Tenere probably stops sooner.
 

Wulfgar

New Member
2011 Site Supporter
Joined
Mar 19, 2011
Messages
121
Location
Birmingham, Alabama
The linked brakes on the Tenere are only linked if you apply the front brake first (or simultaneous with the rear I guess). If you apply only the rear brake, it activates only the rear brake (for better off-road use). That might cause the chirping as well.
 

markjenn

Active Member
Founding Member
Joined
Oct 22, 2010
Messages
2,427
Location
Bellingham, WA
My guess is that using the centerstand test technique that you may need to pull pretty hard on the brake lever to cause much pressure on the rear brake.

The system has to use some type of proportioning valve to distribute pressure from the front to the back. While I don't see anything obvious in the service manual, this valve may be under computer control or have some kind of feedback with the ABS system or speed sensors that prevent a stationary test from telling you anything.

One thing you might try is going out and doing a few quick stops using only the hand brake lever. Then check to see if the rear disc is warm to the touch. And certainly check to see if the bike stops when you use only the rear brake.

I doubt anything is wrong; these systems are pretty foolproof and have all sorts of checks and balances. The chances of it being faulty and simply not working would be extremely low, I'd think.

- Mark
 

SpeedStar

XT12 and DL650
Founding Member
2011 Site Supporter
2012 Site Supporter
2013 Site Supporter
Vendor
Joined
Sep 17, 2010
Messages
1,388
Location
San Diego, Ca
It definately works with just the rear brake. I will try that idea of testing the front only and feeling the temp of the rear disc.
 

fredz43

Well-Known Member
Founding Member
2011 Site Supporter
2012 Site Supporter
2013 Site Supporter
2014 Site Supporter
Joined
Sep 1, 2010
Messages
3,275
Location
IL, the land of straight, flat, boring roads
I know this system is different from the ST1300 linked brakes in hardware, but it evidently works the same way in principle. With the ST1300, you would get the same result on the centerstand. The front wheel has to be rotating and when you apply the front brake, a secondary master cylinder mounted on the caliper is activated by the slight movement of the main caliper as it grasps the front disk. You can test this by manually pushing that SMC upward with one hand and rotating the rear wheel with the other hand and you will feel the rear wheel stop. I don't see a secondary master cylinder on the front calipers of the S10 and that is a good thing, as the ST13's had some issues with them. I think that Yamaha has figured out some way to get the same result without the SMC.
 

troll

New Member
Founding Member
2011 Site Supporter
Joined
Dec 30, 2010
Messages
862
Location
Frozen wastelands of the barren north ( NW Canada
Might help to read some of Wasp's posts on ADV. You can disable the ABS by running in gear on the center stand (ECU thinks there is a fault in system). Any time the wheels are not moving in unison the ABS and traction control system thinks something is wrong. Either the wheels are skidding or there is a fault in the system. 8) SupaT has three brains for covering off engine, ABS and traction control - all called ECU's, all computer tech. Braking is all handled through one cosmic brake modulating valve and the two master cylinders.
 

markjenn

Active Member
Founding Member
Joined
Oct 22, 2010
Messages
2,427
Location
Bellingham, WA
troll said:
Braking is all handled through one cosmic brake modulating valve and the two master cylinders.
The ABS system certain intervenes to release pressure when it senses wheel lock, but the brakes (unlike the throttle) are not directly under computer control and there are no servos involved. The key question here is whether the proportioning valve adjusts front/rear brake bias under computer control - I can't tell with the information I've seen. It might even be possible to use the ABS pump and associated hardware to do double-duty to act as a front-rear proportioning system. OTOH, you can certainly build a linked-braking system like the S10's mechanically with no computer involvement whatsoever.

The FJR service manual has a lot of detailed technical explanations of systems like this, but I don't much in the S10 service manual.

- Mark
 

troll

New Member
Founding Member
2011 Site Supporter
Joined
Dec 30, 2010
Messages
862
Location
Frozen wastelands of the barren north ( NW Canada
not interested in a pissing contest, and I do beg to differ. The service manual has a nice 40 page description of the ABS system and trouble shooting the system. including the ABS ECU function and codes. Definitely worth the read. Pretty controlled system. :-*

I would also suggest the "Feature" section of the service manual which has about 20 pages of description of the operation of the unified braking system (UBS) and how it inter-relates to the ABS. very informative reading as well. 8)
 

martinh

Member
Founding Member
Joined
Dec 3, 2010
Messages
299
Location
New Jeresy
I think for it to work properly if you need to be moving. Both wheels have to be moving for it to work. Running it on the center stand I think I remember reading it will coz an error code and the ABS gets turned off and so does the unified brakes.
 

Camshft

"Nulla tenaci invia est via"
Joined
Apr 8, 2011
Messages
154
Location
Calgary, Alberta
Works perfectly for me. A bit weird when the rear brake pedal depresses by itself!!! I love this feature.
 

GrahamD

Active Member
Founding Member
2011 Site Supporter
2012 Site Supporter
Joined
Oct 9, 2010
Messages
2,146
Location
Blue Mnts - OzStralia
troll said:
not interested in a pissing contest, and I do beg to differ. The service manual has a nice 40 page description of the ABS system and trouble shooting the system. including the ABS ECU function and codes. Definitely worth the read. Pretty controlled system. :-*

I would also suggest the "Feature" section of the service manual which has about 20 pages of description of the operation of the unified braking system (UBS) and how it inter-relates to the ABS. very informative reading as well. 8)
There is also a bit of an inertial sensor in there too isn't there?
 

troll

New Member
Founding Member
2011 Site Supporter
Joined
Dec 30, 2010
Messages
862
Location
Frozen wastelands of the barren north ( NW Canada
GrahamD said:
There is also a bit of an inertial sensor in there too isn't there?
yup, you are right - does a bit of load sensing based on speed and load. The UBS applies rear brake pressure with an electric pump based on the brake ECU's sense of load, inertia and front brake master cylinder pressure. pretty damned sophisticated electronic management. The brake hydraulic unit has 3 or 4 electric solenoids that are controlled by the brake ECU as well. Yamaha claims it is the most advanced electronically managed braking system to date. 8)
 

Jakeboy

What a long, strange trip it's been.
Founding Member
2011 Site Supporter
Joined
Nov 5, 2010
Messages
380
Location
St. Petersburg,FL
I got caught in a heavy downpour yesterday. I hit the front and back at the same time, giving the front way more bias, (of course).

So far, the S10 brakes, IMO, are significantly better than what I had on my DL1000, in the wet. The DL 1000 brakes weren't slouches.

On dry pavement, I know I could stop my old V Strom inside of the S10. Under any other conditions, the S10's brakes are, no doubt, better.

When I first bought a BMW '02 1150 RT, I was skeptical of ABS. I decided to give it a try "on faith". After a good rain, on a wet city street at 60 mph, I stood on the brakes. I hit them panic stop and they made me a believer. BMW's system, at the time was "fully linked".

I'd like to be able to switch off the ABS, totally, as I'd prefer to be able to rear brake only slide and power out.

I'll be doing my off road stuff with the TC "Off", and the ABS system set to off. Just have to get the appropriate bypass/switch.
 

markjenn

Active Member
Founding Member
Joined
Oct 22, 2010
Messages
2,427
Location
Bellingham, WA
troll said:
I would also suggest the "Feature" section of the service manual which has about 20 pages of description of the operation of the unified braking system (UBS) and how it inter-relates to the ABS. very informative reading as well. 8)
Good catch, I missed this as it was in the front of the manual, not back where brake servicing is discussed. Yes, it appears the ABS and UBS systems are unified and the rear brake is operated by the front lever by using the same pump that operates the ABS, all under computer control with deceleration and load as inputs.

It specifically says that the "UBS does not operate before the vehicle starts off" which would mean all bets are off if you're trying to test the system with the vehicle stationary on the centerstand.

- Mark
 

fredz43

Well-Known Member
Founding Member
2011 Site Supporter
2012 Site Supporter
2013 Site Supporter
2014 Site Supporter
Joined
Sep 1, 2010
Messages
3,275
Location
IL, the land of straight, flat, boring roads
Good on ya, Yamaha for designing a UBS that doesn't rely on a troublesome secondary master cylinder as on the ST1300 and GL1800.
 

Don in Lodi

Well-Known Member
Founding Member
2012 Site Supporter
2013 Site Supporter
2014 Site Supporter
Joined
Feb 1, 2011
Messages
5,139
Location
Lodi Kalifornia
Jakeboy said:
I got caught in a heavy downpour yesterday. I hit the front and back at the same time, giving the front way more bias, (of course).

So far, the S10 brakes, IMO, are significantly better than what I had on my DL1000, in the wet. The DL 1000 brakes weren't slouches.

On dry pavement, I know I could stop my old V Strom inside of the S10. Under any other conditions, the S10's brakes are, no doubt, better.

When I first bought a BMW '02 1150 RT, I was skeptical of ABS. I decided to give it a try "on faith". After a good rain, on a wet city street at 60 mph, I stood on the brakes. I hit them panic stop and they made me a believer. BMW's system, at the time was "fully linked".

I'd like to be able to switch off the ABS, totally, as I'd prefer to be able to rear brake only slide and power out.

I'll be doing my off road stuff with the TC "Off", and the ABS system set to off. Just have to get the appropriate bypass/switch.
As noted earlier, if you have the forethought before hitting the dirt, bike on center stand, tranny in second, not sure if there is a speed reached requirement, the ABS will disable. No forethought, unexpected dirt, the ABS hooligan switch would be a great asset for some. Me, I hope to never get this beasty into a situation where I wish it didn't have ABS. She's over 500# after all. She's not meant to be thrown around like that.
 

SpeedStar

XT12 and DL650
Founding Member
2011 Site Supporter
2012 Site Supporter
2013 Site Supporter
Vendor
Joined
Sep 17, 2010
Messages
1,388
Location
San Diego, Ca
Good info. Thanks to everyone for the input on this one. I just wanted to make sure it was functioning properly.
 
Top